[0001] The invention relates to compositions suitable for lowering the molecular weight
of polypropylene, propylene copolymers or polypropylene blends.
[0002] The controlled preparation of polyolefin grades (polymer types having different molar
masses, melt viscosities, densities, molar mass distributions, etc.) by customary
compounding methods, for example by extrusion or injection moulding, is a routine
process employed by polymer manufacturers and polymer processors/ compounders.
[0003] The setting of the desired parameters, for example the melt viscosity, by means of
this polymer process step is critically dependent on the controlled reactivity and
mode of action of the additives employed.
[0004] The use of free-radical formers for modifying the melt viscosity (rheology) of polyolefins
is a generally known method. Whether it results in a lowering of the molecular weight
(degradation) or an increase in the molecular weight (cross linking) depends primarily
on the chemical structure of the polyolefin.
[0005] The reaction of a polymer of the polypropylene type with a free-radical former during
a polymer-processing process generally results in the degradation of the polymer,
whereas polymers of the polyethylene type tend to cross-linking. Examples that may
be mentioned here are polyethylene types, which are obtainable by means of Phillips
catalysts (LDPE) or metallocene catalysts (LLDPE). Exceptions are the polyethylene
types prepared by the Ziegler process, which likewise tend to undergo chain degradation
when processed in the presence of free-radical formers.
[0006] In the case of copolymers and terpolymers or copolymer blends, high proportions of
propylene produce polypropylene-like behaviour, while high proportions of ethylene
result in polyethylene-like behaviour. If the above-mentioned copolymers and terpolymers
or copolymer blends comprise proportions of multiply unsaturated olefins, the probability
of cross linking decreases with decreasing concentration of free double bonds.
[0007] The controlled degradation of polypropylene (PP) to give a product having a lower
molecular weight and a narrower molecular weight distribution is a commercially important
process for producing controlled rheology polypropylene (CR-PP). While specific PP
grades ("reactor grades") are obtainable by optimisation of the synthesis process
or the catalyst systems (metallocene catalyst, Ziegler catalyst), standard PP grades
are frequently modified in process technology by means of a processing step following
the synthesis.
[0008] Known degradation processes proceed either thermally, in particular at temperatures
above 280°C, or in the presence of free-radical generators. In process technology,
the free-radical-induced process is carried out in extruders or injection-moulding
machines at temperatures above 180°C. Suitable free-radical generators are organic
peroxides which are added during the processing step in diluted form (PP Mastermix,
diluted in oil, stabilized on inorganic supports) or directly as a liquid. Under the
given processing conditions, the peroxide disintegrates into free radicals, which
initiate the chain cleavage reactions and form polymers having the desired rheological
properties (melt viscosities). The degradation of a PP to form a product having a
lower molecular weight (higher melt flow rate (MFR)) is generally referred to as a
viscosity-breaking or vis-breaking process.
[0009] CR-PP grades are mainly used for fibre applications and injection-moulding applications
in which low melt viscosities are a prerequisite for economical processing. A wide
range of melt viscosities or molecular weights is nowadays required in process technology.
[0010] A further parameter that influences the processing behaviour of the polymer, in addition
to the molecular weight, is the molecular weight distribution (MWD). While polymer
grades having broad MWDs display improved orientation behaviour of the polymer chains
at low pull-off speeds in a fibre spinning process, the reverse is the case for high
pull off speeds and broad MWDs. For this reason, narrow MWDs are essential at high
pull-off speeds in order to achieve improved continuity in the spinning process.
[0011] The use of peroxides is a drawback, since only a restricted "processing temperature
window" is available because of their decomposition temperatures, which are generally
below the customary temperatures of polymer processing. In addition, strict safety
regulations have to be adhered to during storage, handling and processing of peroxides.
A further disadvantage of peroxides is the impossibility of decomposition-free melt
compounding with polymers. Apart from peroxides, other sources of free radicals are
also known, e.g. C-radical generators based on cumyl systems, but these can be used
only at temperatures above 280°C.
[0012] WO 97/
49737 describes a process for reducing the molecular weight of polymers at temperatures
above 28.0°C using so-called NOR-HALS (HALS: Hindered Amino Light Stabilisers) compounds
containing the group:

[0013] Wherein G is hydrogen or methyl and G
1 and G
2 are each hydrogen, methyl or are together oxo. These known NOR-HALS compounds produce
appreciable polymer degradation only at temperatures above 280°C. Since most polymers
are processed below this temperature at 160-280°C, there is a particular need for
compounds, which can be used at correspondingly lower temperatures.
[0014] WO 01/
90113 discloses a process for reducing the molecular weight of polypropylene, propylene
copolymers or polypropylene blends, wherein a hydroxylamine ester of the formula:

[0015] Wherein among others R
a' is a monoacyl radical and R
1-R
4 are alkyl-substituents; is added to the polypropylene polymers to be degraded, and
the mixture is heated to temperatures below 280°C.
[0016] The present invention relates to the problem of improving that prior art process
further by lowering the process temperature and obtaining polymers of a more homogeneous
(narrow) molecular weight distribution and a reduced level of oligomeric and volatile
decomposition products.
[0017] It has now surprisingly been found that the combination of a hydroxylamine ester
corresponding to the formula above and selected thio compounds shows a significant
synergistic effect, which results in an excellent degradation performance at temperatures
below 220°C. The present invention relates to a polymer composition comprising
- a) At least one hydroxylamine ester of the formula:

Wherein Ra represents acyl;
One of Rb and Rc represents hydrogen and the other one represents a substituent; or
Rb and Rc both represent hydrogen or identical or different substituents; or
Rb and Rc together represent oxygen;
R1 - R4 each represent C1-C6alkyl; and
R5 and R6 each represent independently of one another hydrogen, C1-C6alkyl or C6-C10aryl; or
R5 and R6 together represent oxygen; and
- b) At least one sulphur compound of the formula
R1-S-A (II),
Wherein R1 represents an organic substituent and A represents hydrogen or the group

Wherein B+ represents a cation or a cationic group; and
- c) Polypropylene, propylene copolymers or polypropylene blends.
[0018] The terms and expressions used in the description of the invention preferably have
the following meanings:
Component a)
[0019] In a hydroxylamine ester (I) the term acyl with regard to the definition of R
a preferably represents an acyl radical selected from the group consisting of -C(=O)-H,
-C(=O)-C
1-C
19alkyl, -C(=O)-C
2-C
19alkenyl, -C(=O)-C
2-C
4alkenyl-C
4-C
10aryl, -C(=O)-C
6-C
10aryl, -C(=O)-O-C
1-C
6alkyl, -C(=O)-O-C
6-C
10aryl, -C(=O)-NH-C
1-C
6alkyl, -C(=O)-NH-C
6-C
10aryl and -C(=O)-N(C
1-C
6alkyl)
2;
[0020] C
1-C
19alkyl in the acyl group R
a is, for example, C
1-C
6alkyl, e.g. methyl, ethyl, n-propyl or isopropyl or n-, sec- or tert-butyl or straight-chain
or branched pentyl or hexyl, or C
7-C
19alkyl, e.g. straight-chain or branched heptyl, octyl, isooctyl, nonyl, tert-nonyl,
decyl or undecyl, or straight-chain C
11-C
19alkyl, which together with the -(C=O)- radical forms C
14-C
20alkanoyl having an even number of C-atoms, e.g. lauroyl (C12), myristoyl (C14), palmitoyl
(C16) or stearoyl (C18).
[0021] C
6-C
10Aryl is, for example, carbocyclic monoaryl or diaryl, preferably monoaryl, e.g. phenyl,
which may be monosubstituted or disubstituted by suitable substituents, e.g. C
1-C
4alkyl, e.g. methyl, ethyl or tert-butyl, C
1-C
4alkoxy, e.g. methoxy or ethoxy, or halogen, e.g. chlorine. In the case of disubstitution,
the 2- and 6-positions are preferred.
[0022] The above-mentioned acyl radical R
a may be substituted on the free valences by suitable substituents, e.g. fluorine or
chlorine, and is preferably formyl, acetyl, trifluoroacetyl, pivaloyl, acryloyl, methacryloyl,
oleoyl, cinnamoyl, benzoyl, 2,6-xyloyl, tert-butoxycarbonyl, ethylcarbmoyl or phenylcarbamoyl.
[0023] C
1-C
6Alkyl as R
1 - R
4 is preferably C
1-C
4alkyl, in particular C
1-C
2alkyl, e.g. methyl or ethyl.
[0024] In preferred embodiments, R
1 - R
4 are methyl or ethyl. Alternatively, from one to three substituents R
1 - R
4 are ethyl. The remaining substituents are then methyl.
[0025] R
5 and R
6 are preferably hydrogen. C
1-C
6Alkyl or C
6-C
10aryl as R
5 and R
6 are preferably methyl or phenyl.
[0026] The hydroxylamine esters (I) are known or can be prepared by known methods, e.g.
by acylation of the corresponding >N-OH compound in a customary esterification reaction
with an acid R
a-OH that introduces the group R
a and corresponds to an acyl group selected, for example, from the group consisting
of -C(=O)-H, -C(=O)-C
1-C
19alkyl, -C(=O)-C
2-C
19alkenyl, -C(=O)-C
2-C
4alkenyl-C
6-C
10aryl, -C(=O)-C
6-C
10aryl, -C(=O)-O-C
1-C
6alkyl, -C(=O)-O-C
6-C
10aryl, -C(=O)-NH-C
1-C
6alkyl, -C(=O)-NH-C
6-C
10aryl and -C(=O)-N(C
1-C
6alkyl)
2, or a reactive functional derivative thereof, e.g. the acid halide R
a-X, e.g. the acid chloride, or anhydride, e.g. (R
a)
2O. The hydroxylamine esters (I) and methods for their preparation are described in
WO 01/
30113.
[0027] According to a preferred embodiment the hydroxylamine ester (I) of component a) is
selected from the group consisting of sterically hindered amine derivatives of the
formula:
Wherein n represents an integer from 1 to 4;
Ra represents acyl, R1', R2' and R3' are each, independently of one another, hydrogen or methyl; and G has the following
meanings:
When n = 1,
G represents hydrogen, C1-C18alkyl which may be interrupted by one or more oxygen atoms, 2-cyanoethyl, benzyl,
glycidyl, the C2-C18acyl radical of an aliphatic carboxylic acid, the C7-C15acyl radical of a cycloaliphatic carboxylic acid, the C3-C5acyl radical of an α,β-unsaturated carboxylic acid, or the C7-C15acyl radical of an aromatic carboxylic acid, wherein the carboxylic acid groups may
be substituted in the aliphatic, cycloaliphatic or aromatic part by 1 to 3 -COOZ1 groups, wherein Z1 represents hydrogen, C1-C20alkyl, C3-C12alkenyl, C5-C7cycloalkyl, phenyl or benzyl; or
When n = 2,
G represents C2-C12alkylene, C4-C12alkenylene, xylylene, the C2-C36acyl radical of an aliphatic dicarboxylic acid, the C8-C14acyl radical of a cycloaliphatic or aromatic dicarboxylic acid, or the C8-C14acyl radical of an aliphatic, cycloaliphatic or aromatic dicarbamic acid, where the
dicarboxylic acid group may be substituted in the aliphatic, cycloaliphatic or aromatic
part by 1 or 2 -COOZ1 groups, wherein Z1 is as defined above; or
When n=3,
G represents the trivalent acid radical of an aliphatic, cycloaliphatic or aromatic
tricarboxylic acid, wherein the acid radical may be substituted in the aliphatic,
cycloaliphatic or aromatic part by the group-COOZ1, wherein Z1 is as defined above, or represents the trivalent acid radical of an aromatic tricarbamic
acid or a phosphorus-containing acid or a trivalent silyl radical; or,
When n = 4,
G represents the tetravalent acid radical of an aliphatic, cycloaliphatic or aromatic
tetracarboxylic acid.
[0028] According to a particularly preferred embodiment n represents in a compound (IA)
1 or 2, R
1', R
2' and R
3' each represent hydrogen, R
a represents C
2-C
18alkanoyl or C
3-C
6alkenoyl and G represents the C
12-C
18acyl radical of an aliphatic monocarboxylic acid or the C
4-C
12acyl radical of an aliphatic dicarboxylic acid.
[0029] According to another preferred embodiment the hydroxylamine ester (I) of component
a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein n represents 1 or 2, R
a, R
1', R
2' and R
3' are as defined under the formula IA;
G
1 represents hydrogen, C
1-C
12alkyl, C
2-C
5hydroxyalkyl, C
5-C
7cycloalkyl, C
7-C
8aralkyl, C
2-C
18alkanoyl, C
3-C
5alkenoyl or benzoyl or a group:

Wherein R
a, R
1', R
2' and R
3' are as defined above and G
2 has the following meanings:
When n = 1,
G
2 represents hydrogen, C
1-C
18alkyl, C
3-C
8alkenyl, C
5-C
7cycloalkyl, C
1-C
4alkyl, C
1-C
4alkyl substituted by hydroxy, cyano, alkoxycarbonyl or carbamide, glycidyl or the
groups -CH
2-CH(OH)-Z or CONH-Z, wherein Z is hydrogen, methyl or phenyl; or
When n = 2,
G
2 represents hydrogen, C
2-C
12alkylene, C
6-C
12arylene, xylylene or the -CH
2CH(OH)-CH
2- or -CH
2-CH(OH)-CH
2-O-D-O- groups, wherein D represents C
2-C
10alkylene, C
6-C
15arylene or C
6-C
12cycloalkylene; or, provided that G
1 is other than alkanoyl, alkenoyl or benzoyl, G
2 additionally represents 1-oxo-C
2-C
12alkylene, the bivalent radical of an aliphatic, cycloaliphatic or aromatic dicarboxylic
acid or dicarbamic acid or the -CO- group; or,
When n = 1, G
1 and G
2 together represent the bivalent radical of an aliphatic, cycloaliphatic or aromatic
1,2-dicarboxylic acid or 1,3-dicarboxylic acid.
[0030] According to a particularly preferred embodiment the hydroxylamine ester (I) of component
a) is selected from the group consisting of sterically hindered amine derivatives
of the for mula:

Wherein n represents 1 or 2 and R
a, R
1', R
2' and R
3' are as defined under the formula IA; and, when n = 1 G
3 represents C
2-C
10alkylene, C
2-C
8hydroxyalkylene or C
4-C
32acyloxy-C
2-C
10alkylene, C
4-C
32acyloxy-C
1-C
4alkyl-C
2-C
10alkylene or, when n = 2, represents the group (-CH
2)
2C(CH
2-)
2.
[0031] According to a highly preferred embodiment the hydroxylamine ester (I) of component
a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein R
a, R
1', R
2' and R
3' are as defined under the formula IA and ALK represents C
2-C
10alkylene or C
3-C
10alkylene substituted by at least one substituent selected from the group consisting
of hydroxy, C
4-C
32acyloxy and C
4-C
32acyloxy-C
1-C
4alkyl.
[0032] According to another highly preferred embodiment the hydroxylamine ester (I) of component
a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein R
1' and R
2' independently of one another represent hydrogen or methyl;
R
a represents C
1-C
8 alkanoyl; and
R
a' represents C
8-C
22alkanoyl.
[0033] According to a most preferred embodiment the hydroxylamine ester (I) of component
a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

[0034] According to another embodiment of the invention the hydroxylamine ester (I) of component
a) is selected from the group consisting of sterically hindered amine derivatives
of the formulae:

or

Wherein
n represents 1 or 2;
Ra, R1', R2'and R3' are as defined under the formula IA,
G4 represent hydrogen, C1-C12alkyl, allyl, benzyl, glycidyl or C2-C6alkoxyalkyl; and
G5 has the following meanings:
When n = 1,
G5 represents hydrogen, C1-C12alkyl, C3-C5alkenyl, C7-C9aralkyl, C5-C7cycloalkyl, C2-C4hydroxyalkyl, C2-C6alkoxyalkyl, C6-C10aryl, glycidyl or the groups -(CH2)p-COO-Q or -(CH2)p-O-CO-Q, wherein p represents 1 or 2 and Q represents C1-C4alkyl or phenyl; or
When n = 2,
G5 represents C2-C12alkylene, C4-C12alkenylene, C6-C12arylene, the group
-CH2-CH(OH)-CH2-O-D-O-CH2-CH(OH)-CH2-,
Wherein D represents C2-C10alkylene, C6-C15arylene or C6-C12-cycloalkylene, or the group
-CH2CH(OZ')CH2-(OCH2-CH(OZ')CH2)2-,
Wherein Z' represents hydrogen, C1-C18alkyl, allyl, benzyl, C2-C12alkanoyl or benzoyl,
T1 and T2 each represent, independently of one another, hydrogen, C1-C18alkyl, C6-C10aryl
or C7-C9aralkyl, each of which may be substituted by halogen or C1-C4alkyl, or
[0035] T
1 and T
2 together with the carbon atom connecting them form a C
5-C
14cycloalkane ring.
[0036] According to another preferred embodiment of the invention, the hydroxylamine ester
(I) of component a) is selected from a compound of the formula:

Wherein n = 1 or 2 and G
6 represents the group:

or
Wherein Ra, R1', R2' any R3' are as defined under the formula IA;
E represents -O- or -NG1-;
A represents C2-C6alkylene or -(CH2)3-O-;
x is either 0 or 1;
G1 represents hydrogen, C1-C12alkyl, C2-C5hydroxyalkyl or C5-C7cycloalkyl;
G7 is identical with G6 or represents one of the groups -NG9G10, -OG11, -NHCH2OG11 or -N(CH2OG11)2;
When n=1, G8 is identical with G6 or G7; and,
When n=2, G8 represents the group -E-B-E-, wherein B represents C2-C8alkylene or C2-C8alkylene interrupted by 1 or 2 -NG9- groups, and G9 represents C1-C12alkyl, cyclohexyl, benzyl or C1-C4hydroxyalkyl or the groups:

G10 represents C1-C12alkyl, cyclohexyl, benzyl or C1-C4-hydroxyalkyl; and G11 represents hydrogen, C1-C12alkyl or phenyl; and
G9 and G10 together represent C4-C5alkylene or C4-C5oxaalkylene.
[0037] According to another alternative embodiment of the invention the hydroxylamine ester
(I) of component a) is selected from a compound of the formula:

Wherein n represents an integer greater than two and R
1', R
2' and R
3' are as defined under the formula IA; and B is a bivalent substituent.
[0039] The preparation of these known compounds is described in
WO 01/90113. The hydroxylamine ester (I) of component a) is present in the polymer composition
to be degraded at levels of 10-5000 ppm, preferably 50-1000 ppm.
Component b)
[0040] In a sulphur compound (II) R
1 represents an organic substituent, which is attached to the sulphur atom with a carbon
atom. A represents hydrogen or the group

Wherein B
+ represents a cation or a cationic group.
[0041] An organic substituent R
1, which is attached to the sulphur atom with a carbon atom, is, for example, C
8-C
22alkyl, hydroxy-C
2-C
8alkyl, mercapto-C
2-C
8alkyl, mercapto-C
8-C
20alkyl interrupted by at least one-NH-, mercapto-C
8-C
18alkyl substituted by at least one hydroxy,
[0042] C
6-C
10aryl, C
6-C
10aryl substituted by at least one substituent selected from the group consisting of
C
1-C
4alkyl, 4-thiophenyl and 3-methyl-4-thiophenyl, or C
6-C
10aryl-C
1-C
4alkyl.
[0043] R
1 defined as C
8-C
22alkyl is straight-chain or branched C
8-C
18alkyl e.g. n-octyl, isooctyl types, e.g. 3,4-, 3,5- or 4,5-dimethyl-1-hexyl or 3-
or 5-methyl-1-heptyl, other branched octyl types, such as 1,1,3,3-tetramethylbutyl
or 2-ethylhexyl, n-nonyl, 1,1,3-trimethylhexyl, n-decyl, n-undecyl, 1-methylundecyl,
2-n-butyl-n-octyl, isotridecyl, 2-n-hexyl-n-decyl, 2-n-octyl-n-dodecyl or straight-chain
C
12-C
19alkyl, e.g. lauryl (C12), myristyl (C14), cetyl (C16) or n-octadecyl (C18).
R
1 defined as hydroxy-C
2-C
8alkyl is, for example, 2-hydroxyethyl, 2- or 3-hydroxypropyl, 4-hydroxy-2-hexyl or
4-hydroxy-3-hexyl.
R
1 defined as mercapto-C
2-C
8alkyl is, for example, C
2-C
8alkyl substituted at the terminal carbon atom by a thiol (mercapto) group, e.g. 6-mercapto-n-hexyl
or 5-mercapto-n-pentyl.
R
1 defined as mercapto-C
8-C
20alkyl interrupted by at least one-NH- is exemplified by the substituted diamino-C
2-C
4alkylene groups as shown below:

R
1 defined as mercapto-C
8-C
18alkyl substituted by at least one hydroxy is exemplified by the following mercaptoethylene
glycol groups:

R
1 defined as C
6-C
10aryl is preferably phenyl.
R
1 defined as C
6-C
10aryl substituted by at least one substituent selected from the group consisting of
C
1-C
4alkyl, 4-thiophenyl and 3-methyl-4-thiophenyl is exemplified by the following partial
formula:

Wherein R
a and R
b independently of one another represent hydrogen or methyl.
R
1 defined as C
6-C
10aryl-C
1-C
4alkyl is, for example, benzyl, phen-1-ethyl or phenyl-2-ethyl. A cation or a cationic
group B
+ is for example, an alkali metal cation, e.g. the sodium or potassium ion, the ammonium
ion, the tri-C
1-C
4alkylammonium ion, e.g. the tetramethyl- or tetraethylammonium ion, or the cholinyl
cation.
[0044] Suitable sulphur compounds (II), wherein R
1 represents the above defined organic substituent, which is attached to the sulphur
atom with a carbon atom and A represents hydrogen or the group

Wherein B
+ represents the above defined cation or a cationic group, are represented by the following
structural formulae:

Wherein R
a and R
b independently of one another represent hydrogen or methyl.
[0045] The sulphur compounds (II) are known or can be obtained by known methods.
Component c)
[0046] The polypropylene-type polymers to be degraded can encompass propylene homopolymers,
propylene copolymers and polypropylene blends. Propylene copolymers may contain various
proportions up to 90%, preferably up to 50%, of comonomers. Examples of comonomers
are: olefins such as 1-olefins, e.g. ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene
or 1-octene, isobutylene, cycloolefins, e.g. cyclopentene, cyclohexene, norbornene
or ethylidenenorborne, dienes such as butadiene, isoprene, 1,4-hexadiene, cyclopentadiene,
dicyclopentadiene or norbornadiene; also acrylic acid derivatives and unsaturated
carboxylic anhydrides such as maleic anhydride.
[0047] Polypropylene blends which can be used are mixtures of polypropylene with polyolefins.
Examples are blends of polypropylene with polyethylene selected from the group consisting
of high density polyethylene (HOPE), high molecular weight high density polyethylene
(HMW HDPE), ultra high molecular weight high density polyethylene (UHMW HOPE), medium
density polyethylene (MDPE), low,density polyethylene (LDPE), linear low density polyethylene
(LLDPE), branched low density polyethylene (BLDPE) and ethylene-propylene-diene terpolymers
(EPDM) containing small proportions of diene.
[0048] A highly preferred embodiment of the invention relates to a polymer composition comprising
- a) At least one hydroxylamine ester of the formula:

- b) At least one mercaptane of the formula
R1-S-H (II'),
Wherein R1 represents C8-C18alkyl; and
- c) Polypropylene, propylene copolymers or polypropylene blends.
[0049] Particularly relevant is a polymer composition comprising
- a) At least one hydroxylamine ester of the formula:

- b) At least one S-alkylthiosulphate of the formula

Wherein R1 represents C8-C18alkyl and B+ represents a cation or an cationic group; and
- c) Polypropylene, propylene copolymers or polypropylene blends.
[0050] The polymer composition comprising the above defined components a), b) and c) is
applied in a process for reducing the molecular weight of the above-defined polypropylene,
propylene copolymers of polypropylene blends. That process is another embodiment of
the present invention.
[0051] Another embodiment of the invention is a composition comprising the above defined
components
- a) At least one hydroxylamine ester or a polymer of a hydroxylamine ester (I), wherein
Ra, Rb, Rc and R1-R6 are as defined above; and
- b) At least one sulphur compound of the formula (II), wherein R1 and A are as defined above; to be added as mixture or as individual components to
the polypropylene, propylene copolymers or polypropylene blend to be degraded.
[0052] The above-described compositions comprising hydroxylamine esters (I) and sulphur
compounds (II) are applicable as precursor mixtures or pre-formulated mixtures for
reducing the molecular weight of polypropylene, propylene copolymers and polypropylene
blends to be degraded, where they effect degradation of the polymer chains like the
peroxides customarily used in the prior art.
[0053] The inventive process is characterised in that a composition comprising
- a) At least one hydroxylamine ester or a polymer of a hydroxylamine ester (I), wherein
Ra, Rb, Rc and R1-R6 are as defined above; and
- b) At least one sulphur compound of the formula (II), wherein R1 and A are as defined above, is added to the polypropylene, propylene copolymers or
polypropylene blend to be degraded and the mixture is heated.
[0054] The addition to the polypropylene, propylene copolymers or polypropylene blend can
be carried out in all customary mixing machines in which the polymer is melted and
mixed with the additives. Suitable machines are known to those skilled in the art.
They are predominantly mixers, kneaders and extruders.
[0055] According to a highly preferred embodiment of the invention the composition defined
above is added to the blends of polypropylene with polyethylene selected from the
group consisting of high density polyethylene (HDPE), high molecular weight high density
polyethylene (HMW HOPE), ultra high molecular weight high density polyethylene (UHMW
HOPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear
low density polyethylene (LLDPE), branched low density polyethylene (BLDPE) and ethylene-propylene-diene
terpolymers (EPDM) containing small proportions of diene.
The process is preferably carried out in an extruder by introducing the additive during
processing.
Particularly preferred processing machines are single-screw extruders, contra-rotating
and co-rotating twin-screw extruders, planetary-gear extruders, ring extruders or
co-kneaders. It is also possible to use processing machines provided with at least
one gas removal compartment to which a vacuum can be applied.
[0056] Suitable extruders and kneaders are described, for example, in
Handbuch der Kunststoffextrusion, Vol. 1 Grundlagen, Editors F. Hensen, W Knappe,
H. Potente, 1989, pp. 3-7, ISBN:3-446-14339-4 (Vol. 2 Extrusionsanlagen 1986, ISBN 3-446-14329-7).
[0057] For example, the screw length is 1 - 60 screw diameters, preferably 35-48 screw diameters.
The rotational speed of the screw is preferably 10 - 600 rotations per minute (rpm),
very particularly preferably 25 - 300 rpm.
[0058] The maximum throughput is dependent on the screw diameter, the rotational speed and
the driving force. The process of the present invention can also be carried out at
a level lower than maximum throughput by varying the parameters mentioned or employing
weighing machines delivering dosage amounts.
[0059] If a plurality of components is added, these can be premixed or added individually.
[0060] The polymers may need to be subjected to an elevated temperature for a sufficient
period of time, so that the desired degradation occurs. The temperature is generally
above the softening point of the polymers.
[0061] In a preferred embodiment of the process of the present invention, a temperature
range lower than 280°C, particularly from about 160°C to 280°C is employed. In a particularly
preferred process variant, the temperature range from about 200°C to 270°C is employed.
The period of time necessary for degradation can vary as a function of the temperature,
the amount of material to be degraded and the type of, for example, extruder used.
It is usually from about 10 seconds to 20 minutes, in particular from 20 seconds to
10 minutes.
[0062] In the process for reducing the molecular weight (degradation process) of the polypropylene
polymers, the above-described compositions comprising hydroxylamine esters (I) and
sulphur compounds (II) are present in concentrations, based on the amount of polymers
to be degraded, of from about 0.001 to 5.0% by weight, in particular from 0.01 to
2.0% by weight and particularly preferably from 0.02 to 1.0% by weight. The hydroxylamine
esters (I) and sulphur compounds (II) can be added as individual compounds or as mixtures
to the polymer to be degraded. The ratio of hydroxylamine esters (I) and sulphur compounds
(II) may vary within wide limits, e.g. from 1.0:20.0 wt.% to 20.0 : 1.0 wt.%, preferably
1.0 : 1.0 wt.% to 10.0 : 1.0 wt.%.
[0063] While the sometimes volatile decomposition products (smoke) of peroxides can lead
to discolouration or odour in the degraded polymers, very little discolouration and
odour occur in the case of the polymers degraded by means of hydroxylamine esters
(I) and sulphur compounds (II).
[0064] Incorporation into the polymers can be carried out, for example, by mixing the above-described
hydroxylamine esters (I) and sulphur compounds (II) or mixtures thereof and, if desired,
further additives into the polymers using the methods customary in process technology.
[0065] Incorporation can, alternatively, also be carried out at temperatures, which do not
yet cause decomposition of the polymers (latent compound). The polymers prepared in
this way can subsequently be heated a second time and subjected to an elevated temperature
for a sufficient period of time so that the desired polymer degradation occurs.
[0066] The NOR-compounds (I) and sulphur compounds (II) can also be added to the polymers
to be degraded in the form of a master batch, in which these compounds are present,
for example, in a concentration of from about 1.0 - 25.0% by weight. The master batch
(concentrate) can be produced at temperatures, which do not yet cause decomposition
of the compounds of the present invention.
[0067] This provides a product, which is defined by specific dosage amounts and may be compounded
with other additives. The master batch can then be compounded with the polymer to
be degraded at a temperature above the decomposition temperature of the hydroxylamine
ester (I).
[0068] The present invention therefore further provides a concentrate in which the NOR-compounds
(I) and sulphur compounds (II) are present in a concentration of 1.0-25.0% by weight
and which can be added to the polymer to be degraded. The desired product is thus
obtainable in an advantageous two-stage process.
[0069] In a specific embodiment, suitable additives, such as metal salts, e.g. of Ca, Fe,
Zn or Cu, are added to the polymers to be degraded.
[0070] It has surprisingly been found that oxides, hydroxides and carbonates of metals in
the oxidation state II aid the degrading action. Preference is therefore given to
compositions which, in addition to the above-described NOR-compounds (I) and sulphur
compounds (II), further comprise 0.1-10 parts of metal salt per part of NOR-compound
(I). Particular preference is given to concentrations of 0.5 - 10 parts of metal salt
selected from the group consisting of CaO, CaCO
3, ZnO, ZnCO
3, MgO, MgCO
3 or Mg(OH)
2 per part of the NOR-compound (I) and sulphur compound (II) mixture.
[0071] Apart from the hydroxylamine esters (I) and sulphur compounds (II), further additives
can also be present in the polymer, e.g. sulphur based pigments like ultramarine blue,
light stabilizers of the 2-(2-hydroxyphenyl)-1,3,5-triazine type which are known from
the patent literature, e.g.
US-A-4,619,956, EP-A-434 608, US-A-5,198,498, US-A-5,322,868, US-A-5,369,140, US-A-5,298,067, WO-94/18278, EP-A-704 437,
GB-A-2,297,091 or
WO-96/28431. Further examples of additives are listed in
WO 01/90113.
[0072] In a specific embodiment of the invention, the polymer to be degraded is prepared
with addition of the above-described hydroxylamine esters (I) and sulphur compounds
(II) together with selected antioxidants and processing stabilizers or mixtures of
these. Examples of preferred compounds are:
Pentaerythrityl tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (Irganox®
1010), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (IRGANOX 1076),
3,3',3',5,5',5'-hexa-tert-butyl-α,α',α'-(mesitylene-2,4,6-triyl)tri-p-cresol (IRGANOX
1330), calcium diethyl bis(((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl)phosphonate)
(IRGANOX 1425), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)trione
(IRGANOX 3114), tris(2,4-di-tert-butylphenyl) phosphite (Irgafos® 168), tris(nonylphenyl)
phosphite, tetrakis(2,4-di-tert-butylphenyl) [1,1-biphenyl]-4,4'-diylbisphosphonite
(IRGANOX P-EPQ), didodecyl 3,3'-thiodipropionate (IRGANOX PS 800), dioctadecyl 3,3'-thiodipropionate
(IRGANOX PS 802); 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one (IRGANOX
HP 136) and distearylhydroxylamine (Irgastab® FS 042).
[0073] Further additives are antacids, such as calcium stearate or zinc stearate, hydrotalcites
or calcium lactate, calcium lactylate from Patco (Pationic®).
[0074] In a specific embodiment, further sources of free radicals, e.g. a suitable bis azo
compound, a peroxide or a hydroperoxide, in addition to the hydroxylamine esters (I)
and sulphur compounds (II) can be added to the polymers to be degraded.
[0075] Suitable bis azo compounds are commercially available, e.g. 2,2'-azobisisobutyronitrile,
2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile),
1,1'-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(isobutyramide) dihydrate, 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile,
dimethyl 2,2'-azobisisobutyrate, 2-(carbamoylazo)isobutyronitrile, 2,2'-azobis(2,4,4-trimethylpentane),
2,2'-azobis(2-methylpropane), 2,2'-azobis(N,N'-dimethyleneisobutyramidine) as free
base or hydrochloride, 2,2'-azobis(2-amidinopropane) as free base or hydrochloride,
2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} or 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}.
[0076] Suitable peroxides and hydroperoxides are commercially available, e.g. acetylcyclohexanesulphonyl
peroxide, diisopropyl peroxydicarbonate, tert-amyl perneodecanoate, tert-butylperneodecanoate,
tert-butylperpivalate, tert-amylperpivalate, bis(2,4-dichlorobenzoyl) peroxide, diisononanoyl
peroxide, didecanoyl peroxide, dioctanoyl peroxide, dilauroyl peroxide, bis(2-methylbenzoyl)
peroxide, disuccinoyl peroxide, diacetyl peroxide, dibenzoyl peroxide, tert-butyl
per-2-ethylhexanoate, bis(4-chlorobenzoyl) peroxide, tert-butyl perisobutyrate, tert-butyl
permaleate, 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane,
tert-butyl peroxyisopropyl carbonate, tert-butyl perisononaoate, 2,5-dimethylhexane
2,5-dibenzoate, tert-butyl peracetate, tert-amyl perbenzoate, tert-butyl perbenzoate,
2,2-bis(tert-butylperoxy)butane, 2,2-bis (tert-butylperoxy)propane, dicumyl peroxide,
2,5-dimethylhexane 2,5-di-tert-butylperoxid, 3-tert-butylperoxy-3-phenyl phthalide,
di-tert-amyl peroxide, α,α'-bis(tert-butylperoxyisopropyl) benzene, 3,5-bis(tert-butylperoxy)-3,5-dimethyl-1,2-dioxolane,
di-tert-butyl peroxide, 2,5-dimethylhexyne 2,5-di-tert-butyl peroxide, 3,3,6,6,9,9-hexamethyl-1,2,4,5-tetraoxacyclononane,
p-menthane hydroperoxide, pinane hydroperoxide, diisopropylbenzene mono-α-hydroperoxide,
cumene hydroperoxide or tert-butyl hydroperoxide.
[0077] The abovementioned bis azo compounds, peroxides or hydroperoxides are added to the
polymers to be degraded in amounts smaller than those customary when they are used
alone in the processes of the prior art.
[0078] In a further preferred embodiment of the present invention, at least 2 different
free-radical initiators having different decomposition temperatures are employed,
so that the degradation of the polymers may occur in 2 stages. This process is also
referred to as sequential degradation.
[0079] Suitable compositions comprise, for example, the free-radical initiators of the invention
and the abovementioned peroxides or a combination of the NOR-compounds described in
WO 97/
49737 and the hydroxylamine esters (I) and sulphur compounds (II) described above.
[0080] It is essential that the two decomposition temperatures are sufficiently apart for
effecting to a 2-stage process. For example, a peroxide having a decomposition temperature
in the range of about 180 - 220°C can be combined with a mixture of a hydroxylamine
ester (I) and sulphur compound (II) having decomposition temperatures in the range
of about 240 - 280°C or a mixture of a hydroxylamine ester (I) and sulphur compound
(II) having decomposition temperatures in the range of about 240 - 280°C can be combined
with an NOR-compound described in
WO 97/
49737 having a decomposition temperature above 300°C.
[0081] It is of course also possible to use mixtures of free-radical generators having different
decomposition temperatures in the process.
[0082] According to a preferred embodiment the degradation is advantageously carried out
in the presence of small amounts of free nitroxyl radicals. A more readily controllable
degradation of the polymer is achieved, which leads to more constant melting properties.
Suitable nitroxyl radicals are known and described in
US-A-4,581,429 or
EP-A-621 878. Open-chain structures are described in
WO 99/03894 and
WO 00/07981. Furthermore, NO-derivatives of the piperidine type are described in
WO 99/67298 and in
British Patent Specification 2,335,190. Other NO-derivatives of heterocyclic compounds are described in
British Patent Specification 2, 342, 649.
[0083] The following Examples illustrate the invention:
Abbreviations
Rpm: rotations per minute
Examples
1. Materials and Methods
1.1 Compounds and Compound Mixtures Tested
1.1.1 Thio-Compound 1 ("Thio-1")
[0084]

1.1.2 Thio-Compound 2 ("Thio-2")
[0085]

1.1.2.1 Preparation of Thio-2
[0086] A 1 I flask equipped with stirrer, thermometer and a reflux condenser is charged
with 116.3 g (0.3488 mol) octadecyl bromide, 55.3 g (0.3498 mol) sodium thiosulphate,
2 g tetrabutylammonium chloride, 350 ml ethanol (96%) and 175 ml water. The mixture
is gently refluxed with stirring under nitrogen for 18.5 h. A clear solution is formed
which is slowly cooled to 22°C under stirring. The white precipitate is filtered off
with suction and the filter cake washed with water (2 x 400 ml) and dried at 60°C
/100 mbar. 133.82 g (98.7%) Thio-2 is obtained as a white powder.
1.1.3 Hydroxylamine Ester 1 ("NOR 1")
[0087]

1.2 Controlled degradation of polypropylene by means of NOR compounds
[0088] After adding the additives and additive mixtures listed in Tables 1-3 and the basic
level stabilization mixture (0.15% of IRGANOX B 225 and 0.05% of calcium stearate;
IRGANOX® B 225: 1:1 mixture of Irgafos®168 and IRGANOX® 1010) commercial polypropylene
(Moplen HF 500 N®, manufacturer:
Basell) is extruded on a twin-screw extruder ZSK 25 (Wemer & Pfleiderer) at a temperature
of T
max = 250°C (heating zones 1 - 6), a throughput of 4 kg/h and 100 rpm. The resulting
polymer is strand granulated in a water bath. The melt viscosity (MFR) is determined
in accordance to ISO 1133. A large increase in the melt flow rate indicates substantial
chain degradation.
2. Results
[0089]
2.1
Table 1 (Effect of thio additive Component b))
Examples |
Additives |
MFR (230/2.16) |
A1*) |
- (Control) |
16 |
A2*) |
0.025% NOR 1 |
41 |
A3*) |
0.05% NOR 1 |
65 |
A4*) |
0.025% Thio 1 |
23 |
A5*) |
0.05% Thio 1 |
31 |
A6 |
0.025% NOR 1 + 0.025% Thio 1 |
190 |
A7 |
0.0125% NOR 1 + 0.0375% Thio 1 |
86 |
A8 |
0.0375% NOR 1 + 0.0125% Thio 1 |
250**) |
A9 |
0.05% NOR 1 + 0.05% Thio 1 |
595**) |
A10 |
0.025% NOR 1 + 0.075% Thio 1 |
240**) |
A11 |
0.075% NOR 1 + 0.025% Thio 1 |
940**) |
Additives added as polymer concentrates (3.3% NOR 1 in PP, 5% Thio 1 in PP); Polymer
density at 230° C = 0.75 g/cm3;
*) Comparative Example;
**) Measured by means of a die with diameter = 1.05 mm instead of standard die in
accordance to ISO 1133. |
2.2
Table 2 (Improved degradation performance at temperatures below 250°C)
Examples |
Additives |
MFR (230/2.16) Extrusion Tmax: 210°C |
MFR (230/2.16) Extrusion Tmax: 250°C |
B1*) |
- |
14 |
17 |
B2*) |
0.033% NOR 1 |
38 |
64 |
B3*) |
0.0062% Thio 2 |
14 |
16 |
B4 |
0.025% NOR 1 + 0.0031% Thio 2 |
42 |
89 |
B5 |
0.033% NOR 1 + 0.0041% Thio 2 |
62 |
119 |
B6 |
0.05% NOR 1 + 0.0061% Thio 2 |
98 |
190 |
Additives added as polymer concentrates (3.3% NOR 1 in PP, 0.41% Thio 1 in PP);
Polymer density at 230° C = 0.75 g/cm3; *) Comparative Example |
2.3
Table 3 (Influence of thio concentration on degradation performance)
Examples |
Additives |
MFR (230/2.16) |
C1*) |
- |
17 |
C2*) |
0.05% NOR 1 |
87 |
C3 |
0.05% NOR 1 + 0.05% Thio 2 |
1400**) |
C4 |
0.05% NOR 1 + 0.025% Thio 2 |
1160**) |
C5 |
0.05% NOR 1 + 0.0125% Thio 2 |
430**) |
C6 |
0.05% NOR 1 + 0.0031% Thio 2 |
170 |
Additives added as polymer concentrates (3.3% NOR 1 in PP, 0.41% Thio 1 in PP); Polymer
density at 230° C = 0.75 g/cm3;
*) Comparative Example;
**) Measured by means of a die with diameter = 1.05 mm instead of standard die in
accordance with ISO 1133. |
3. Conclusion
[0090] The addition of a mixture of hydroxylamine ester (I) and thio compound (II) results
in an increased degradation of polypropylene, which is reflected by higher MFR values
as compared with the comparative examples.
[0091] In contrast to the use of the hydroxylamine ester (I) as a single component, the
admixture with the thio compounds results in considerably higher polymer degradation
(higher MFR values) at lower concentrations and even at lower processing temperatures.
1. A polymer composition comprising
a) At least one hydroxylamine ester of the formula:

Wherein Ra represents acyl;
One of Rb and Rc represents hydrogen and the other one represents a substituent; or Rb and Rc both represent hydrogen or identical or different substituents; or
Rb and Rc together represent oxygen;
R1 - R4 each represent C1-C6alkyl; and
R5 and R6 each represent independently of one another hydrogen, C1-C6alkyl or C6-C10aryl; or
R5 and R6 together represent oxygen; and
b) At least one sulphur compound of the formula
R1-S-A (II),
Wherein R1 represents an organic substituent and A represents hydrogen or the group

Wherein B+ represents a cation or a cationic group; and
c) Polypropylene, propylene copolymers or polypropylene blends.
2. A polymer composition according to claim 1, wherein the hydroxylamine ester (I) of
component a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein n represents an integer from 1 to 4;
Ra represents acyl, R1', R2' and R3' are each, independently of one another, hydrogen or methyl; and G has the following
meanings:
When n = 1,
G represents hydrogen, C1-C18alkyl which may be interrupted by one or more oxygen atoms, 2-cyanoethyl, benzyl,
glycidyl, the C2-C18acyl radical of an aliphatic carboxylic acid, the C7-C15acyl radical of a cycloaliphatic carboxylic acid, the C3-C5acyl radical of an α,β-unsaturated carboxylic acid, or the C7-C15acyl radical of an aromatic carboxylic acid, wherein the carboxylic acid groups may
be substituted in the aliphatic, cycloaliphatic or aromatic part by 1 to 3 -COOZ1 groups, wherein Z1 represents hydrogen, C1-C20alkyl, C3-C12alkenyl, C5-C7cycloalkyl, phenyl or benzyl; or
When n = 2,
G represents C2-C12alkylene, C4-C12alkenylene, xylylene, the C2-C36acyl radical of an aliphatic dicarboxylic acid, the C8-C14acyl radical of a cycloaliphatic or aromatic dicarboxylic acid, or the C8-C14acyl radical of an aliphatic, cycloaliphatic or aromatic dicarbamic acid, where the
dicarboxylic acid group may be substituted in the aliphatic, cycloaliphatic or aromatic
part by 1 or 2 -COOZ1 groups, wherein Z1 is as defined above; or
When n = 3,
G represents the trivalent acid radical of an aliphatic, cycloaliphatic or aromatic
tricarboxylic acid, wherein the acid radical may be substituted in the aliphatic,
cycloaliphatic or aromatic part by the group-COOZ1, wherein Z1 is as defined above, or represents the trivalent acid radical of an aromatic tricarbamic
acid or a phosphorus-containing acid or a trivalent silyl radical; or,
When n = 4,
G represents the tetravalent acid radical of an aliphatic, cycloaliphatic or aromatic
tetracarboxylic acid.
3. A polymer composition according to claim 2, wherein in compound (IA) n represents
1 or 2, R1', R2' and R3' each represent hydrogen, Ra represents C2-C18alkanoyl or C3-C6alkenoyl and G represents the C12-C18acyl radical of an aliphatic monocarboxylic acid or the C4-C12acyl radical of an aliphatic dicarboxylic acid.
4. A polymer composition according to claim 1, wherein the hydroxylamine ester (I) of
component a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein n represents 1 or 2, R
a, R
1', R
2' and R
3' are as defined under the formula IA;
G1 represents hydrogen, C1-C12alkyl, C2-C5hydroxyalkyl, C5-C7cycloalkyl, C7-C8aralkyl, C2-C18alkanoyl, C3-C5alkenoyl or benzoyl or a group:

Wherein Ra, R1', R2' and R3' are as defined above and G2 has the following meanings: When n = 1,
G2 represents hydrogen, C1-C18alkyl, C3-C8alkenyl, C5-C7cycloalkyl, C1-C4alkyl, C1-C4alkyl substituted by hydroxy, cyano, alkoxycarbonyl or carbamide, glycidyl or the
groups -CH2-CH(OH)-Z or CONH-Z, wherein Z is hydrogen, methyl or phenyl; or
When n = 2,
G2 represents hydrogen, C2-C12alkylene, C6-C12arylene, xylylene or the -CH2CH(OH)-CH2- or -CH2-CH(OH)-CH2-O-D-O- groups, wherein D represents C2-C10alkylene, C6-C15arylene or C6-C12cycloalkylene; or, provided that G1 is other than alkanoyl, alkenoyl or benzoyl, G2 additionally represents 1-oxo-C2-C12alkylene, the bivalent radical of an aliphatic, cycloaliphatic or aromatic dicarboxylic
acid or dicarbamic acid or the -CO- group; or,
When n = 1, G1 and G2 together represent the bivalent radical of an aliphatic, cycloaliphatic or aromatic
1,2-dicarboxylic acid or 1,3-dicarboxylic acid.
5. A polymer composition according to claim 1, wherein the hydroxylamine ester (I) of
component a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein n represents 1 or 2 and R
a, R
1', R
2' and R
3' are as defined under the formula IA; and, when n = 1 G
3 represents C
2-C
10alkylene, C
2-C
8hydroxyalkylene or C
4-C
32acyloxy-C
2-C
10alkylene, C
4-C
32acyloxy-C
1-C
4alkyl-C
2-C
10alkylene or, when n = 2, represents the group (-CH
2)
2C(CH
2-)
2.
6. A polymer composition according to claim 1, wherein the hydroxylamine ester (I) of
component a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein R
a, R
1', R
2' and R
3' are as defined under the formula IA and ALK represents C
2-C
10alkylene or C
3-C
10alkylene substituted by at least one substituent selected from the group consisting
of hydroxy, C
4-C
32acyloxy and C
4-C
32acyloxy-C
1-C
4alkyl.
7. A polymer composition according to claim 6, wherein the hydroxylamine ester (I) of
component a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:

Wherein R
1' and R
2' independently of one another represent hydrogen or methyl;
R
a represents C
1-C
8 alkanoyl; and
R
a' represents C
8-C
22alkanoyl.
8. A polymer composition according to claim 7 herein the hydroxylamine ester (I) of component
a) is selected from the group consisting of sterically hindered amine derivatives
of the formula:
9. A polymer composition according to claim 1, wherein the hydroxylamine ester (I) of
component a) is selected from the group consisting of sterically hindered amine derivatives
of the formulae:

or

Wherein
n represents 1 or 2;
Ra, R1', R2' and R3' are as defined under the formula IA,
G4 represent hydrogen, C1-C12alkyl, allyl, benzyl, glycidyl or C2-C6alkoxyalkyl; and
G5 has the following meanings:
When n = 1,
G5 represents hydrogen, C1-C12alkyl, C3-C5alkenyl, C7-C9aralkyl, C5-C7cycloalkyl, C2-C4hydroxyalkyl, C2-C6alkoxyalkyl, C6-C10aryl, glycidyl or the groups -(CH2)p-COO-Q or -(CH2)p-O-CO-Q, wherein p represents 1 or 2 and Q represents C1-C4alkyl or phenyl; or When n = 2,
G5 represents C2-C12alkylene, C4-C12alkenylene, C6-C12arylene, the group
-CH2-CH(OH)-CH2-O-D-O-CH2-CH(OH)-CH2-,
Wherein D represents C2-C10alkylene, C6-C15arylene or C6-C12-cycloalkylene, or the group
-CH2CH(OZ')CH2-(OCH2-CH(OZ')CH2)2-,
Wherein Z' represents hydrogen, C1-C18alkyl, allyl, benzyl, C2-C12alkanoyl or benzoyl,
T1 and T2 each represent, independently of one another, hydrogen, C1-C18alkyl, C6-C10aryl or C7-C9aralkyl, each of which may be substituted by halogen or C1-C4alkyl, or
T1 and T2 together with the carbon atom connecting them form a C5-C14cycloalkane ring.
10. A polymer composition according to claim 1, wherein the hydroxylamine ester (I) of
component a) is selected from a compound of the formula:

Wherein n = 1 or 2 and G
6 represents the group:

or
Wherein R
a, R
1', R
2' and R
3' are as defined under the formula IA;
E represents -O- or -NG
1-;
A represents C
2-C
6alkylene or -(CH
2)
3-O-;
x is either 0 or 1;
G
1 represents hydrogen, C
1-C
12alkyl, C
2-C
5hydroxyalkyl or C
5-C
7cycloalkyl;
G
7 is identical with G
6 or represents one of the groups -NG
9G
10, -OG
11, -NHCH
2OG
11 or -N(CH
2OG
11)
2;
When n=1, G
8 is identical with G
6 or G
7; and,
When n=2, G
8 represents the group -E-B-E-, wherein B represents C
2-C
8alkylene or C
2-C
8alkylene interrupted by 1 or 2 -NG
9- groups, and G
9 represents C
1-C
12alkyl, cyclohexyl, benzyl or C
1-C
4hydroxyalkyl or the groups:

G
10 represents C
1-C
12alkyl, cyclohexyl, benzyl or C
1-C
4-hydroxyalkyl; and G
11 represents hydrogen, C
1-C
12alkyl or phenyl; and
G
9 and G
10 together represent C
4-C
5alkylene or C
4-C
5oxaalkylene.
11. A polymer composition according to claim 1, wherein the hydroxylamine ester (I) of
component a) is selected from a compound of the formula:

Wherein n represents an integer greater than two and R
1', R
2' and R
3' are as defined under the formula IA; and B is a bivalent substituent.
12. A polymer composition according to claim 1, Wherein the sulphur compound (II) of component
b) is selected from the group consisting of mercaptanes of the formula
R
1-S-H (II')
And S-alkylthiosulphates of the formula

Wherein R
1 represents C
8-C
18alkyl and B
+ represents a cation or a cationic group.
13. A polymer composition according to claim 1 comprising
a) At least one hydroxylamine ester of the formula:

b) At least a mercaptane of the formula
R1-S-H (II'),
Wherein R1 represents C8-C18alkyl; and
c) Polypropylene, propylene copolymers or polypropylene blends.
14. A polymer composition according to claim 1 comprising
a) At least one hydroxylamine ester of the formula:

b) At least one S-alkylthiosulphate of the formula

Wherein R1 represents C8-C18alkyl and B+ represents a cation or an cationic group; and
c) Polypropylene, propylene copolymers or polypropylene blends.
15. A composition suitable for reducing the molecular weight of polypropylene, propylene
copolymers or polypropylene blends, which comprises
a) At least one hydroxylamine ester or a polymer of a hydroxylamine ester of the formula
(I), wherein Ra, Rb, Rc and R1-R6 are as defined in claim 1; and
b) At least one sulphur compound of the formula (II), wherein R1 and A are as defined in claim 1.
16. A process for reducing the molecular weight of polypropylene, propylene copolymers
of polypropylene blends,
characterised in that a composition comprising
a) At least one hydroxylamine ester or a polymer of a hydroxylamine ester of the formula

Wherein Ra represents acyl;
One of Rb and Rc represents hydrogen and the other one represents a substituent; or Rb and Rc each represent identical or different substituents; or
Rb and Rc together represent oxygen;
R1 - R4 each represent C1-C6alkyl; and
R5 and R6 each represent independently of one another hydrogen, C1-C6alkyl or C6-C10aryl; or
R5 and R6 together represent oxygen; and
b) At least one sulphur compound of the formula
R1-S-A (II),
Wherein R1 represents an organic substituent and A represents hydrogen or the group

Wherein B+ represents a cation or a cationic group; is added to the polypropylene, propylene
copolymers or polypropylene blend to be degraded and the mixture is heated.
17. A process according to claim 16, characterised in that a temperature range lower than 280°C is employed.
18. A process according to claim 16, characterised in that the composition is added to a blend of polypropylene with polyethylene selected from
the group consisting of high density polyethylene (HDPE), high molecular weight high
density polyethylene (HMW HDPE), ultra high molecular weight high density polyethylene
(UHMW HYPE), medium density polyethylene (MDPE), low density polyethylene (LDPE),
linear low density polyethylene (LLDPE), branched low density polyethylene (BLDPE)
and ethylene-propylene-diene terpolymers (EPDM) containing small proportions of diene.
1. Polymer-Zusammensetzung, umfassend
a) mindestens einen Hydroxylaminester der Formel:

worin Ra Acyl wiedergibt;
einer von Rb und Rc Wasserstoff wiedergibt und der andere einen Substituenten wiedergibt; oder
Rb und Rc beide Wasserstoff oder gleiche oder verschiedene Substituenten wiedergeben; oder
Rb und Re zusammen Sauerstoff wiedergeben;
R1-R4 jeweils C1-C6-Alkyl wiedergeben; und
R5 und R6 jeweils unabhängig voneinander Wasserstoff, C1-C6-Alkyl oder C6-C10-Aryl wiedergeben; oder
R5 und R6 zusammen Sauerstoff wiedergeben; und
b) mindestens eine Schwefel-Verbindung der Formel
R1-S-A (II),
worin R1 einen organischen Substituenten wiedergibt und A Wasserstoff oder die Gruppe

wiedergibt,
worin B+ ein Kation oder eine kationische Gruppe wiedergibt; und
c) Polypropylen, Propylen-Copolymere oder Polypropylen-Blends.
2. Polymer-Zusammensetzung nach Anspruch 1, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus der Gruppe, bestehend aus sterisch gehinderten Amin-Derivaten
der Formel:

worin n eine ganze Zahl von 1 bis 4 wiedergibt;
R
a Acyl wiedergibt, R
1', R
2' und R
3' jeweils, unabhängig voneinander, Wasserstoff oder Methyl darstellen; und G die nachstehenden
Bedeutungen aufweist:
wenn n = 1,
G Wasserstoff, C
1-C
18-Alkyl, das durch ein oder mehrere Sauerstoff-Atome unterbrochen sein kann, 2-Cyanoethyl,
Benzyl, Glycidyl, den C
2-C
18-Acyl-Rest von einer aliphatischen Carbonsäure, den C
7-C
15-Acyl-Rest von einer cycloaliphatischen Carbonsäure, den C
3-C
5-Acyl-Rest von einer α,β-ungesättigten Carbonsäure, oder den C
7-C
15-Acyl-Rest von einer aromatischen Carbonsäure wiedergibt, wobei die Carbonsäure-Gruppen
in dem aliphatischen, cycloaliphatischen oder aromatischen Teil mit 1 bis 3 Gruppen
-COOZ
1, worin Z
1 Wasserstoff, C
1-C
20-Alkyl, C
3-C
12-Alkenyl, C
5-C
7-Cycloalkyl, Phenyl oder Benzyl wiedergibt, substituiert sein können; oder
wenn n = 2,
G C
2-C
12-Alkylen, C
4-C
12-Alkenylen, Xylylen, den C
2-C
36-AcylRest von einer aliphatischen Dicarbonsäure, den C
8-C
14-AcylRest von einer cycloaliphatischen oder aromatischen Dicarbonsäure, oder den C
8-C
14-Acyl-Rest von einer aliphatischen, cycloaliphatischen oder aromatischen Dicarbamidsäure
wiedergibt, wobei die Dicarbonsäure-Gruppe in dem aliphatischen, cycloaliphatischen
oder aromatischen Teil mit 1 oder 2 Gruppen -COOZ
1, worin Z
1 wie vorstehend definiert ist, substituiert sein kann; oder
wenn n = 3,
G den dreiwertigen Säure-Rest von einer aliphatischen, cycloaliphatischen oder aromatischen
Tricarbonsäure wiedergibt, wobei der Säure-Rest in dem aliphatischen, cycloaliphatischen
oder aromatischen Teil mit der Gruppe -COOZ
1, worin Z
1 wie vorstehend definiert ist, substituiert sein kann, oder den dreiwertigen Säure-Rest
von einer aromatischen Tricarbamidsäure oder einer Phosphor-enthaltenden Säure, oder
einen dreiwertigen Silyl-Rest wiedergibt; oder,
wenn n = 4,
G den vierwertigen Säure-Rest von einer aliphatischen, cycloaliphatischen oder aromatischen
Tetracarbonsäure wiedergibt.
3. Polymer-Zusammensetzung nach Anspruch 2, worin in einer Verbindung (IA) n 1 oder 2
wiedergibt, R1', R2' und R3' jeweils Wasserstoff wiedergeben, Ra C2-C18-Alkanoyl oder C3-C6-Alkenoyl wiedergibt und G den C12-C18-Acyl-Rest von einer aliphatischen Monocarbonsäure oder den C4-C12-Acyl-Rest von einer aliphatischen Dicarbonsäure wiedergibt.
4. Polymer-Zusammensetzung nach Anspruch 1, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus der Gruppe, bestehend aus sterisch gehinderten Amin-Derivaten
der Formel:

worin n 1 oder 2 wiedergibt, R
a, R
1', R
2' und R
3' wie unter der Formel IA definiert sind;
G
1 Wasserstoff, C
1-C
12-Alkyl, C
2-C
5-Hydroxyalkyl, C
5-C
7-Cycloalkyl, C
7-C
8-Aralkyl, C
2-C
18-Alkanoyl, C
3-C
5-Alkenoyl oder Benzoyl oder eine Gruppe:

worin R
a, R
1', R
2' und R
3' wie vorstehend definiert sind, wiedergibt und G
2 die nachstehenden Bedeutungen aufweist:
wenn n = 1,
G
2 Wasserstoff, C
1-C
18-Alkyl, C
3-C
8-Alkenyl, C
5-C
7-Cycloalkyl, C
1-C
4-Alkyl, C
1-C
4-Alkyl, substituiert mit Hydroxy, Cyano, Alkoxycarbonyl oder Carbamid, Glycidyl oder
die Gruppen -CH
2-CH(OH)-Z oder CONH-Z, worin Z Wasserstoff, Methyl oder Phenyl darstellt, wiedergibt;
oder
wenn n = 2,
G
2 Wasserstoff, C
2-C
12-Alkylen, C
6-C
12-Arylen, Xylylen oder die Gruppen -CH
2CH(OH)-CH
2- oder -CH
2-CH(OH)-CH
2-O-D-O- wiedergibt, worin D C
2-C
10-Alkylen, C
6-C
15-Arylen oder C
6-C
12-Cycloalkylen wiedergibt; oder, mit der Maßgabe, dass G
1 von Alkanoyl, Alkenoyl oder Benzoyl verschieden ist, G
2 zusätzlich 1-Oxo-C
2-C
12-alkylen, den zweiwertigen Rest von einer aliphatischen, cycloaliphatischen oder aromatischen
Dicarbonsäure oder Dicarbamidsäure oder die Gruppe -COwiedergibt; oder,
wenn n = 1, G
1 und G
2 zusammen den zweiwertigen Rest von einer aliphatischen, cycloaliphatischen oder aromatischen
1,2-Dicarbonsäure oder 1,3-Dicarbonsäure wiedergeben.
5. Polymer-Zusammensetzung nach Anspruch 1, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus der Gruppe, bestehend aus sterisch gehinderten Amin-Derivaten
der Formel:

worin
n 1 oder 2 wiedergibt und R
a, R
1', R
2' und R
3' wie unter der Formel IA definiert sind; und, wenn n = 1, G
3 C
2-C
10-Alkylen, C
2-C
8-Hydroxyalkylen oder C
4-C
32-Acyloxy-C
2-C
10-alkylen, C
4-C
32-Acyloxy-C
1-C
4-alkyl-C
2-C
10-alkylen wiedergibt oder,
wenn n = 2, die Gruppe (-CH
2)
2C(CH
2-)
2 wiedergibt.
6. Polymer-Zusammensetzung nach Anspruch 1, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus der Gruppe, bestehend aus sterisch gehinderten Amin-Derivaten
der Formel:

worin
R
a, R
1', R
2' und R
3' wie unter der Formel IA definiert sind; und, ALK C
2-C
10-Alkylen oder C
3-C
10-Alkylen, substituiert mit mindestens einem Substituenten, ausgewählt aus der Gruppe,
bestehend aus Hydroxy, C
4-C
32-Acyloxy und C
4-C
32-Acyloxy-C
1-C
4-alkyl, wiedergibt.
7. Polymer-Zusammensetzung nach Anspruch 6, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus der Gruppe, bestehend aus sterisch gehinderten Amin-Derivaten
der Formel:

worin R
1' und R
2' unabhängig voneinander Wasserstoff oder Methyl wiedergeben;
R
a C
1-C
8-Alkanoyl wiedergibt; und
R
a' C
8-C
22-Alkanoyl wiedergibt.
8. Polymer-Zusammensetzung nach Anspruch 7, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus der Gruppe, bestehend aus sterisch gehinderten Amin-Derivaten
der Formel:
9. Polymer-Zusammensetzung nach Anspruch 1, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus der Gruppe, bestehend aus sterisch gehinderten Amin-Derivaten
der Formeln:

oder

worin
n 1 oder 2 wiedergibt;
R
a, R
1', R
2' und R
3' wie unter der Formel IA definiert sind;
G
4 Wasserstoff, C
1-C
12-Alkyl, Allyl, Benzyl, Glycidyl oder C
2-C
6-Alkoxyalkyl wiedergibt; und
G
5 die nachstehenden Bedeutungen aufweist:
wenn n = 1,
G
5 Wasserstoff, C
1-C
12-Alkyl, C
3-C
5-Alkenyl, C
7-C
9-Aralkyl, C
5-C
7-Cycloalkyl, C
2-C
4-Hydroxyalkyl, C
2-C
6-Alkoxyalkyl, C
6-C
10-Aryl, Glycidyl oder die Gruppen -(CH
2)
p-COO-Q oder -(CH
2)
P-O-CO-Q, worin p 1 oder 2 wiedergibt und Q C
1-C
4-Alkyl oder Phenyl wiedergibt; oder
wenn n = 2,
G
5 C
2-C
12-Alkylen, C
4-C
12-Alkenylen, C
6-C
12-Arylen, die Gruppe -CH
2-CH (OH) -CH
2-O-D-O-CH
2-CH (OH) -CH
2-
wiedergibt, worin D C
2-C
10-Alkylen, C
6-C
15-Arylen oder C
6-C
12-Cycloalkylen, oder die Gruppe -CH
2CH(OZ')CH
2-(OCH
2-CH(OZ')CH
2)
2-
wiedergibt, worin Z' Wasserstoff, C
1-C
18-Alkyl, Allyl, Benzyl, C
2-C
12-Alkanoyl oder Benzoyl wiedergibt,
T
1 und T
2 jeweils, unabhängig voneinander, Wasserstoff, C
1-C
18-Alkyl, C
6-C
10-Aryl oder C
7-C
9-Aralkyl wiedergeben, wobei jeder davon mit Halogen oder C
1-C
4-Alkyl substituiert sein kann, oder
T
1 und T
2 zusammen mit dem Kohlenstoff-Atom, das sie verbindet, einen C
5-C
14-Cycloalkan-Ring bilden.
10. Polymer-Zusammensetzung nach Anspruch 1, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus einer Verbindung der Formel:

worin n = 1 oder 2 und G
6 die Gruppe:

wiedergibt, worin R
a, R
1', R
2' und R
3' wie unter der Formel IA definiert sind;
E -O- oder -NG
1- wiedergibt;
A C
2-C
6-Alkylen oder -(CH
2)
3-O- wiedergibt;
x entweder 0 oder 1 ist;
G
1 Wasserstoff, C
1-C
12-Alkyl, C
2-C
5-Hydroxyalkyl oder C
5-C
7-Cycloalkyl wiedergibt;
G
7 mit G
6 identisch ist oder eine von den Gruppen -NG
9G
10, -OG
11, -NHCH
2OG
11 oder -N(CH
2OG
11)
2 wiedergibt;
wenn n = 1, G
8 mit G
6 oder G
7 identisch ist; und,
wenn n = 2, G
8 die Gruppe -E-B-E- wiedergibt, worin B C
2-C
8-Alkylen oder C
2-C
8-Alkylen, unterbrochen durch 1 oder 2 Gruppen -NG
9-, wiedergibt und G
9 C
1-C
12-Alkyl, Cyclohexyl, Benzyl oder C
1-C
4-Hydroxyalkyl oder die Gruppen:

wiedergibt,
G
10 C
1-C
12-Alkyl, Cyclohexyl, Benzyl oder C
1-C
4-Hydroxyalkyl wiedergibt; und G
11 Wasserstoff, C
1-C
12-Alkyl oder Phenyl wiedergibt; und
G
9 und G
10 zusammen C
4-C
5-Alkylen oder C
4-C
5-Oxaalkylen wiedergeben.
11. Polymer-Zusammensetzung nach Anspruch 1, worin der Hydroxylaminester (I) von Komponente
a) ausgewählt ist aus einer Verbindung der Formel:

worin
n eine ganze Zahl größer als zwei wiedergibt und R
1', R
2' und R
3' wie unter der Formel IA definiert sind; und
B einen zweiwertigen Substituenten darstellt.
12. Polymer-Zusammensetzung nach Anspruch 1, worin die Schwefel-Verbindung (II) von Komponente
b) ausgewählt ist aus der Gruppe, bestehend aus Mercaptanen der Formel
R
1-S-H (II')
und S-Alkylthiosulfaten der Formel

worin R
1 C
8-C
18-Alkyl wiedergibt und B
+ ein Kation oder eine kationische Gruppe wiedergibt.
13. Polymer-Zusammensetzung nach Anspruch 1, umfassend
a) mindestens einen Hydroxylaminester der Formel:

b) mindestens ein Mercaptan der Formel
R1-S-H (II'),
worin R1 C8-C18-Alkyl wiedergibt; und
c) Polypropylen, Propylen-Copolymere oder Polypropylen-Blends.
14. Polymer-Zusammensetzung nach Anspruch 1, umfassend
a) mindestens einen Hydroxylaminester der Formel:

b) mindestens ein S-Alkylthiosulfat der Formel

worin R1 C8-C18-Alkyl wiedergibt und B+ ein Kation oder eine kationische Gruppe wiedergibt; und
c) Polypropylen, Propylen-Copolymere oder Polypropylen-Blends.
15. Zusammensetzung, geeignet zum Vermindern des Molekulargewichts von Polypropylen, Propylen-Copolymeren
oder Polypropylen-Blends, die umfasst
a) mindestens einen Hydroxylaminester oder ein Polymer von einem Hydroxylaminester
der Formel (I), worin Ra, Rb, Rc und R1-R6 wie in Anspruch 1 definiert sind; und
b) mindestens eine Schwefel-Verbindung der Formel (II), worin R1 und A wie in Anspruch 1 definiert sind.
16. Verfahren zum Vermindern des Molekulargewichts von Polypropylen, Propylen-Copolymeren
oder Polypropylen-Blends,
dadurch gekennzeichnet, dass eine Zusammensetzung, umfassend
a) mindestens einen Hydroxylaminester oder ein Polymer von einem Hydroxylaminester
der Formel

worin Ra Acyl wiedergibt;
einer von Rb und Rc Wasserstoff wiedergibt und der andere einen Substituenten wiedergibt; oder
Rb und Rc jeweils gleiche oder verschiedene Substituenten wiedergeben; oder
Rb und Rc zusammen Sauerstoff wiedergeben;
R1-R4 jeweils C1-C6-Alkyl wiedergeben; und
R5 und R6 jeweils unabhängig voneinander Wasserstoff,
C1-C6-Alkyl oder C6-C10-Aryl wiedergeben; oder
R5 und R6 zusammen Sauerstoff wiedergeben; und
b) mindestens eine Schwefel-Verbindung der Formel
R1-S-A (II),
worin R
1 einen organischen Substituenten wiedergibt und A Wasserstoff oder die Gruppe

wiedergibt,
worin B
+ ein Kation oder eine kationische Gruppe wiedergibt; zu dem Polypropylen, Propylen-Copolymeren
oder Polypropylen-Blend gegeben wird, die abgebaut werden sollen, und das Gemisch
erhitzt wird.
17. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass ein Temperatur-Bereich geringer als 280°C angewendet wird.
18. Verfahren nach Anspruch 16, dadurch gekennzeichnet, dass die Zusammensetzung zu einem Blend von Polypropylen mit Polyethylen, ausgewählt aus
der Gruppe, bestehend aus hoch dichtem bzw. Niederdruck-Polyethylen (HDPE), hoch dichtem
bzw. Niederdruck-Polyethylen mit hohem Molekulargewicht (HMW HDPE), hoch dichtem bzw.
Niederdruck-Polyethylen mit sehr hohem Molekulargewicht (UHMW HDPE), mittel dichtem
Polyethylen (MDPE), nieder dichtem bzw. Hochdruck-Polyethylen (LDPE), linear nieder
dichtem bzw. Hochdruck-Polyethylen (LLDPE), verzweigtem nieder dichtem bzw. Hochdruck-Polyethylen
(BLDPE) und Ethylen-Propylen-Dien-Terpolymeren (EPDM), die geringe Anteile an Dien
enthalten, gegeben wird.
1. Composition polymériques comprenant :
a) au moins un ester hydroxylamine de formule

dans laquelle, Ra représente acyle,
un des Rb et Rc représente hydrogène et l'autre représente un substituant ; ou
Rb et Rc représentent tous deux hydrogène ou des substituants identiques ou différents ; ou
Rb et Rc ensemble représentent oxygène ;
R1 - R4 représentent chacun C1-C6alkyle ; et
R5 et R6 représentent chacun indépendamment l'un de l'autre un autre hydrogène, C1-C6alkyle ou C6-C10aryle ; ou
R5 et R6 ensemble représentent oxygène ; et
b) au moins un composé soufré de formule
R1-S-A (II),
dans laquelle, R1 représente un substituant organique et A représente hydrogène ou le groupe

dans laquelle, B+ représente un cation ou un groupe cationique ; et
c) des copolymères polypropylène, propylène ou des mélanges polypropylènes.
2. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir du groupe composé
de dérivés d'amine avec encombrement stérique de formule

dans laquelle, n représente un nombre entier de 1 à 4 ;
R
a représente acyle, R
1', R
2' et R
3' sont chacun, indépendamment les uns des autres, hydrogène ou méthyle ; et G possède
les significations suivantes :
lorsque n = 1,
G représente hydrogène, C
1-C
18alkyle qui peut être interrompu par un ou plusieurs atomes d'oxygène, 2-cyanoéthyle,
benzyle, glycidyle, le radical C
2-C
18acyle d'un acide carboxylique aliphatique, le radical C
7-C
15acyle d'un acide carboxylique cycloaliphatique, le radical C
3-C
5acyle d'un acide carboxylique α,β-insaturé, ou le radical C
7-C
15acyle d'un acide carboxylique aromatique,
caractérisé en ce que les groupes d'acide carboxylique peuvent être substitués dans la partie aliphatique,
cycloaliphatique ou aromatique par de 1 à 3 groupes -COOZ
1, dans lesquels Z
1 représentent hydrogène, C
1-C
20alkyle, C
3-C
12alkényle, C
5-C
7cycloalkyle, phényle ou benzyle ; ou
lorsque n = 2,
G représente C
2-C
12alkylène, C
4-C
12alkénylène, xylylène, le radical C
2-C
36acyle d'un acide dicarboxylique aliphatique, le radical C
8-C
14acyle d'un acide dicarboxylique cycloaliphatique ou aromatique, ou le radical C
8-C
14acyle d'un acide dicarbamique aliphatique, cycloaliphatique ou aromatique,
caractérisé en ce que le groupe acide dicarboxylique peut être substitué dans la partie aliphatique, cycloaliphatique
ou aromatique par 1 ou 2 groupes -COOZ
1, dans lesquels Z
1 est tel que défini ci-dessus ; ou
lorsque n = 3,
G représente le radical acide trivalent d'un acide tricarboxylique aliphatique, cycloaliphatique
ou aromatique,
caractérisé en ce que le radical acide peut être substitué dans la partie aliphatique, cycloaliphatique
ou aromatique par le groupe -COOZ
1, dans lequel Z
1 est tel que défini ci-dessus, ou représente le radical acide trivalent d'un acide
tricarbamique aromatique ou d'un acide contenant du phosphore ou d'un radical silyle
trivalent ; ou
lorsque n = 4,
G représente le radical acide tétravalent d'un acide tétracarboxylique aliphatique,
cycloaliphatique ou aromatique.
3. Composition polymérique selon la revendication 2, caractérisée en ce que dans un composé (IA), n représente 1 ou 2, R1', R2' et R3' représentent chacun hydrogène, Ra représente C2-C18alkanoyle ou C3-C6alkenoyle et G représente le radical C12-C18acyle d'un acide monocarboxylique aliphatique ou le radical C4-C12acyle d'un acide dicarboxylique aliphatique.
4. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir du groupe composé
de dérivés d'amine avec encombrement stérique de formule :

dans laquelle, n représente un nombre entier de 1 ou 2, R
a, R
1', R
2' et R
3' sont tels que définis à la formule IA
G
1 représente hydrogène, un C
1-C
12alkyle, C
2-C
5hydroxyalkyle, C
5-C
7cycloalkyle, C
7-C
8aralkyle, C
2-C
18alkanoyle, C
3-C
5alkenoyle ou benzoyle ou un groupe

dans lequel, R
a, R
1', R
2' et R
3' sont tels que définis ci-dessus et G
2 possède l'une des significations suivantes :
lorsque n = 1,
G
2 représente hydrogène, C
1-C
18alkyle, C
3-C
8alkényle, C
5-C
7cycloalkyle, C
1-C
4alkyle, C
1-C
4alkyle substitué par hydroxy, cyano, alcoxycarbonyle ou carbamide, glycidyle ou les
groupes -CH
2-CH(OH)-Z ou CONH-Z, dans lesquels Z est hydrogène, méthyle ou phényle ; ou
lorsque n = 2,
G
2 représente hydrogène C
2-C
12alkylène, C
6-C
12arylène, xylylène ou les groupes - CH
2CH(OH)-CH
2- ou -CH2-CH(OH)-CH
2-O-D-O, dans lesquels D représente C
2-C
10alkylène, C
6-C
15arylène ou C
6-C
12cycloalkylène ; ou, à condition que G
1 soit autre qu'alkanoyle, alkenoyle ou benzoyle, G
2 représente également 1-oxo-C
2-C
12alkylène, le radical bivalent d'un acide dicarboxylique ou d'un acide dicarbamique
aliphatique, cycloaliphatique ou aromatique ou le groupe -CO- ; ou
lorsque n = 1, G
1 et G
2 ensemble représentent le radical bivalent d'un acide 1,2-dicarboxylique ou 1,3-dicarboxylique
aliphatique, cycloaliphatique ou aromatique.
5. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir du groupe composé
de dérivés d'amine avec encombrement stérique de formule

dans laquelle, n représente 1 ou 2 et R
a, R
1', R
2' et R
3' sont tels que définis à la formule IA ; et, lorsque n = 1, G
3 représente C
2-C
10alkylène, C
2-C
8hydroxyalkylène ou C
4-C
32acyloxy-C
2-C
10alkylène, ou lorsque n = 2, il représente le groupe (-CH
2)
2C(CH
2-)
2.
6. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir du groupe composé
de dérivés d'amine avec encombrement stérique de formule

dans laquelle, R
a, R
1', R
2' et R
3' sont tels que définis à la formule IA et ALK représente C
2-C
10alkylène ou C
3-C
10alkylène substitué par au moins un substituant sélectionné à partir du groupe composé
d'hydroxy, C
4-C
32acyloxy et C
4-C
32acyloxy-C
1-C
4alkyle.
7. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir du groupe composé
de dérivés d'amine avec encombrement stérique de formule

dans laquelle, R
1' et R
2', indépendamment l'un de l'autre, représentent hydrogène
ou méthyle ;
R
a représente C
1-C
8 alkanoyle ; et
R
a' représente C
8-C
22alkanoyle.
8. Composition polymérique selon la revendication 7,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir du groupe composé
de dérivés d'amine avec encombrement stérique de formule
9. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir du groupe composé
de dérivés d'amine avec encombrement stérique de formule

ou

dans laquelle,
n représente 1 ou 2 ;
R
a, R
1', R
2' et R
3' sont tels que définis à la formule IA,
G
4 représente hydrogène, C
1-C
12alkyle, allyle, benzyle, glycidyle ou C
2-C
6alcoxyalkyle ; et
G
5 possède les significations suivantes :
Lorsque n = 1,
G
5 représente hydrogène, C
1-C
12alkyle, C
3-C
5alkényle, C
7-C
9aralkyle, C
5-C
7cycloalkyle, C
2-C
4hydroxyalkyle, C
2-C
6alcoxyalkyle, C
6-C
10aryle, glycidyle ou les groupes -(CH
2)
p-COO-Q ou -(CH
2)
p-O-CO-Q, dans lesquels p représente 1 ou 2 et Q représente C
1-C
4alkyle ou phényle ; ou
Lorsque n = 2,
G
5 représente C
2-C
12alkylène, C
4-C
12alkénylène, C
6-C
12arylène, le groupe
-CH
2-CH(OH)-CH
2-O-D-O-CH
2-CH(OH)-CH
2-,
dans lequel, D représente C
2-C
10alkylène, C
6-C
15arylène ou C
6-C
12-cycloalkylène, ou le groupe
-CH
2CH(OZ')CH
2-(OCH
2-CH(OZ')CH
2)
2-,
dans lequel, Z' représente hydrogène, C
1-C
18alkyle, allyle, benzyle, C
2-C
12alkanoyle ou benzoyle,
T
1 et T
2 représentent chacun, indépendamment l'un de l'autre, hydrogène, C
1-C
18alkyle, C
6-C
10aryle ou C
7-C
9aralkyle, chacun d'eux peut être substitué par halogène ou C
1-C
4alkyle, ou
T
1 et T
2 de pair avec l'atome de carbone qui les relient, forment un cycle C
5-C
14cycloalkane.
10. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir d'un composé de
formule

dans laquelle, n = 1 ou 2 et G
6 représente le groupe :

ou
dans laquelle, R
a, R
1', R
2' et R
3' sont tels que définis à la formule IA,
E représente -O- ou -NG
1-;
A représente C
2-C
6alkylène ou -(CH
2)
3-O-;
x est soit 0, soit 1 ;
G
1 représente hydrogène, C
1-C
12alkyle, C
2-C
5hydroxyalkyle ou C
5-C
7cycloalkyle;
G
7 est identique à G
6 ou représente un des groupes -NG
9G
10, -OG
11, NHCH
2OG
11 ou
-N(CH
2OG
11)
2;
Lorsque n = 1, G
8 est identique à G
6 ou G
7 et,
Lorsque n = 2, G
8 représente le groupe -E-B-E-, dans lequel B représente C
2-C
8alkylène ou C
2-C
8alkylène interrompu par 1 ou 2 groupes -NG
9-, et G
9 représente C
1-C
12alkyle, cyclohexyle, benzyle ou C
1-C
4hydroxyalkyle ou les groupes :

G
10 représente C
1-C
12alkyle, cyclohexyle, benzyle ou C
1-C
4-hydroxyalkyle ; et G
11 représente hydrogène, C
1-C
12alkyle ou phényle ; et
G
9 et G
10 ensemble représentent C
4-C
5alkylène ou C
4-C
5oxaalkylène.
11. Composition polymérique selon la revendication 1,
caractérisé en ce que l'ester hydroxylamine (I) du composant a) est sélectionné à partir d'un composé de
formule

dans laquelle, n représente un nombre entier supérieur à 2 et R
1', R
2' et R
3' sont tels que définis à la formule IA, et B est un substituant bivalent.
12. Composition polymérique selon la revendication 1, dans laquelle le composé soufré
(II) du composant b) est sélectionné à partir du groupe composé de mercaptanes de
formule
R1-S-H (II')
et de S-alkylthiosulfates de formule

dans laquelle, R
1 représente C
8-C
18alkyle et B
+ représente un cation ou un groupe cationique.
13. Composition polymérique selon la revendication 1, comprenant
a) au moins un ester hydroxylamine de formule

b) au moins un mercaptane de formule
R1-S-H (II')
dans laquelle, R1 représente C8-C18alkyle ; et
c) des copolymères polypropylène, propylène ou des mélanges polypropylènes.
14. Composition polymérique selon la revendication 1, comprenant
a) au moins un ester hydroxylamine de formule

b) au moins un S-alkylthiosulfate de formule

dans laquelle, R1 représente C8-C18alkyle et B+ représente un cation ou un groupe cationique ;
c) des copolymères polypropylène, propylène ou des mélanges polypropylènes.
15. Composition convenant pour réduire le poids moléculaire de copolymères polypropylène,
propylène ou des mélanges polypropylènes, qui comprend
a) au moins un ester hydroxylamine ou un polymère d'un ester hydroxylamine de formule
(I), dans laquelle, Ra, Rb, Rc et R1-R6 sont tels que définis à la revendication 1 ; et
b) au moins un composé soufré de formule (II) dans laquelle R1 et A sont tels que définis à la revendication 1.
16. Procédé de réduction du poids moléculaire de copolymères polypropylène, propylène
ou des mélanges polypropylènes,
caractérisé en ce que la composition comprend
a) au moins un ester hydroxylamine ou un polymère d'un ester hydroxylamine de formule

dans laquelle, Ra représente acyle ;
un des Rb et Rc représente hydrogène et l'autre représente un substituant ; ou
Rb et Rc représentent chacun des substituants identiques ou différents ; ou
Rb et Rc représentent ensemble oxygène ;
R1-R4 représentent chacun C1-C6alkyle ; et
R5 et R6 représentent chacun indépendamment l'un de l'autre, hydrogène, C1-C6alkyle ou C6-C10aryle
R5 et R6 représentent ensemble oxygène ; et
b) au moins un composé soufré de formule
R1-S-A (II),
dans laquelle, R
1 représente un substituants organique et A représente hydrogène ou le groupe

dans lequel B+ représente un cation ou un groupe cationique ;
est ajouté aux copolymères polypropylène, propylène ou aux mélanges polypropylènes,
de façon à être dégradés et le mélange est chauffé.
17. Procédé selon la revendication 16, caractérisé en ce qu'une gamme de température inférieure à 280°C est employée.
18. Procédé selon la revendication 16, caractérisé en ce que la composition est ajoutée à un mélange de polypropylène avec du polyéthylène sélectionné
à partir du groupe composé de polyéthylène à forte densité (HDPE), de polyéthylène
à forte densité et à haut poids moléculaire (HMW HDPE), de polyéthylène à forte densité
et à ultra haut poids moléculaire (UHMW HDPE), de polyéthylène à densité moyenne (MDPE),
de polyéthylène à faible densité (LDPE), de polyéthylène à faible densité linéaire
(LLDPE), de polyéthylène ramifié à faible densité (BLDPE) et de terpolymères éthylène-propylène
(EPDM) contenant de petites proportions de diène.